Film supporting and driving means



Feb- 7, 1939- w. v. BRENBARGER Er AL 2,146,170

FILM SUPPORTING AND DRIVING MEANS Snow,

Feb. 7, 1939. w. v BRENBARGER ET AL 2,145,170

FILM SUPPORTING AND DRIVING MEANS Filed Nov. 17, 1937` 2 sheets-sheet 2 Patented Feb. 7, 1939 UNITED STATES PATENT OFFICE William V. Brenbarger, Bell, and John F. Van

\ Lueven, Los Angeles, Calif.

Application November 17, 1937, Serial No. 175,052

10 Claims.

This invention relates generally to apparatus for developing motion picture film and particularly to means for supporting and moving the film through the developing, fixing and washing tanks and through the drying cabinets.

In film developing it is the usual practice to run the film in a continuous length through a series of tanks containing developing solutions, rinse solutions, xing solutions, and Wash solutions, and to run it through one or more drying cabinets. A series of film carrying rollers is provided at the top and at the bottom of the tanks and in the drying cabinet so that the film forms a multiplicty of loops in passing through each tank and through the drying cabinet. The film is driven either by sprocket wheels located at suitably spaced distances or by the frictional engagement of the film with certain of the rolls which are driven, or by a combination 20 of both of these means.

This invention employs the frictional driving rollers alone and is not concerned with the sprocket system of driving the film.

As is well known in the art, the film, as it becomes wet in developing, swells and stretches and subsequently as it is dried shrinks again to approximately its original size. In developing machines utilizing the frictional driving of the film, various means are employed to keep the lm under the proper tension, so that it will frictionally engage the driving rollers suiciently to be driven thereby through the tanks. Such tensioning means must provide for the stretching and shrinking of the film. In order to accomplish this there is usually providedv means for enlarging and reducing the size of the film loops or some of the loops which the film forms as it is wound about the various rollers.

One common method of accomplishing this is to have certain of the lower rollers weighted and mounted for vertical movement. 'Ihe disadvantage of this construction lies in the fact that the film must support the weight of the lower rollers and their mounting means, thereby tending to mechanically stretch the film and distort the images and sound track thereon. It therefore is an object of this invention to provide means for supporting and moving the film adapted to accommodate for the natural stretching and shrinking of the film without causing the film to support or bear the weight of any portion of the apparatus, so that there will be no possibility y 55 Certain developing machines provide driven (Cl. 27h-2.3)

lower rollers so that if the film stretches the slack developed thereby leaves or drops below the driving rollers with the consequent result that the film is not driven by such rollers and the slack tends to work back to the starting point of 5 the driving mechanism. Very often in such machines the film accumulates upon the bottom of the tank in a series of convolutions and may easily be scratched and may even fail to be properly drawn back upon the proper rollers when 10 the slack is subsequently taken up. The disadvantages of this system are obvious, and it therefore is an object of this invention to provide .a means for supporting and driving the lm so that the film cannot become slack at any point l5 throughout the mechanism.

Certain other developing machines place the film under considerable tension at the point where it leaves the apparatus and rely upon this tension to raise free running lower rollers into engagement with driving means so that the lower rollers are driven. This system has the obvious disadvantage of placing considerable strain upon the film, since the film itself must overcome the means which yieldably holds the lower rollers out of driving position. Great danger of mechanically stretching the film is always present in such apparatus. Therefore, it is a further object of this invention to provide supporting and driving means for the film which only places a minimum tension upon the film sufficient for it to be frictionally driven by the driving rollers.

Furthermore, many of the devices in use at the present time draw the film from the develop- .55 ing machine at a constant speed and hence, due to shrinkage and stretching of the film during the developing process, must necessarily run the film into the developing solution intermittently. The disadvantage of this condition is the fact that the film may be improperly developed, especially the sound track, due to its intermittent entrance into the developing solution. Intermittent feeding of the film into the developing solution is one of the greatest faults of present day equipment.

In view of the disadvantages of the ordinary film supporting and driving apparatus it is a particular object of this invention to provide apparatus that will feed the film into the developing solution at a constant rate and from which the film may come out at varying speeds depending upon the stretch and shrinkage of the particular film stock during development.

Generally it is an object of this invention to provide film supporting and driving means which will steadily feed the lmi into the developing solution and which will automatically compensate for the natural elongation of the film when wet and which will also compensate for the shrinkage of the film as it dries and which, when so compensating for the changing in size of the film, will not place an abnormal or undesirable amount of strain upon the film, nor allow the film to accumulate in slack loops.

This is accomplished by providing lm supporting and driving means, the initial driving rollers of which rotate at a slightly slower peripheral speed than the other driving rollers and by providing means for disengaging any or all of the driving rollers if the tension on the film approaches a given amount.

These and other objects will be apparent from the drawings and the following description thereof.

Referring to the drawings- Fig. 1 is a fragmentary sectional elevation of a developing tank showing film supporting and driving means of this invention in position therein. The plane of the section is indicated by line I-I of Fig. 2;

Fig. 2 is a sectional elevation on line 2-2 of Fig. 1.

Particularly describing the invention, reference numeral I I generally indicates a developing tank which may be of any ordinary construction. It is the ordinary practice to removably mount the film supporting and driving mechanism on top of the tank and accordingly reference numerals I2 and I2' indicate channel members for supporting the film supporting and driving mechanism.

These channels may be suitably connected by means of cross members (not shown), such construction being within the scope of the ordinary mechanic. f

The film supporting and driving mechanism generally comprises a plurality of sections of upper and lower iilm carrying rollers. The upper film carrying rollers are designated generally by reference numeral I3 and the lower film carrying rollers by reference numeral I4. The lm I5 is looped about these rollers successively as indicated. Certain of the upper rollers are driven by peripheral contact with driving rolls I6 and I3' which are driven by a suitable mechanism, subsequently to be described.

For the purpose of guiding the film to the first section of upper and lower rollers, there is provided tensioning roller I8 which is rotatably mounted on a stud shaft i9 on the bracket 29 which is secured to the channel member I2 by bolts 2i. Above this roller there is provided the roller 22 mounted on the pin 23 which is in turn mounted on an arm 24. 'I'his arm is pivotally mounted at 25 on the channel I2. The film passes over and around the right side of the roller 22 and then around the left side and bottom of roller I8 to roller I3a from which it passes in loops successively about the various rollers I3 and I4 of the first section of upper and lower rollers 27.

The film passes from the last of the upper 'rollers in the first section 21 to the second section of upper and lower rollers, generally indicated by reference numeral 28 and successively passes over the various rollers in this section and then passes to the next section in the same tank and other tanks. It is to be understood of course, that as many of these sections of upper and lower rollers maybe provided as is necessary to conduct the film through the various solutions needed in the development of the lm and through the drying cabinets.

This pair of rollers I8 and 22 provide a necessary drag or tension on the film to insure its being drawn into the machine by the first section of the upper rollers at a steady, constant rate.

This invention contemplates driving the film through frictional contact with certain of the upper rollers which are driven by frictional contact with driving rolls I6 and IS. It further contemplates having the first section of rollers driven at a slower speed than the succeeding sections, in order to compensate for the natural stretching of the film when wet. The invention also contemplates means for permitting the upper rollers I3 to move away from and out of driving engagement with the driving roll when a given amount of tension is placed on the film.

Referring to the details in construction, the lower rollers I4 of each of the sections of upper and lower rollers are rotatably mounted upon a shaft 30. Both the upper and lower rollers are of the ordinary double-anged type commonly used in film developing apparatus, however, it has been found desirable to employ large sized rollers so that they may be more easily rotated by the film. A collar 3| is provided at each end of the bank of rollers to keep them in proper position upon the shaft. The shaft 30 is supported at each end upon cross members 32. The

cross members are hung in the developing tank by means of rods 33 which extend upwardly through suitable holes 34 in the members I2 and I2' and are provided with the nuts 35 threadably engaging the upper end and nuts 36 at the lower end.

As distinguished from the comparatively rigid mounting of the lower rollers, the upper rollers I3 are mounted for yieldable vertical movement. Referring to the details of the mounting of the upper rollers, these rollers are rotatably mounted on a shaft 38 and are held in position thereon by collars 39. This upper shaft is carried by saddle members 40 which are provided with the grooves 4I into which the shaft 38 ts and is secured by means of pins 42. These saddle members 40 are dependently mounted in the tank upon supporting rods 43 which extend upwardly and slidably through suitable holes 44 in the members I2 and I2. These rods are provided with the compression springs 45 and nuts 46. The saddle members 40 are provided with the holes 41 which are of greater diameter than the rods 33 and through which said rods extend. This construction provides for yieldable downwardly vertical movement of the upper rollers i3, the saddle members being slidable on the rods 33.

For the purpose of driving certain of the upper rollers I3 in each of the sections of upper and lower rollers, the driving rolls I6 and I6' are provided. Reference number I6 indicates the iirst set of driving rolls located over the first section of upper and lower film carrying rollers, said section being at the beginning of or entrance to the developing apparatus. It is to be understood of course that as many of the sets of driving rolls I6' are to be provided as there are sections of upper and lower film carrying rollers 28 throughout the developing apparatus. Each of the driving rolls I 8 is designed to have a peripheral speed slower than the succeeding sets of driving rolls I6 throughout the machine.

For the details in the construction of these rolls, the rolls I6 are rigidly mounted on a drive shaft in any suitable manner. This shaft passes through holes I in the channels I2 and I2 respectively, and is supported at one end by a bearing 52. The driving rolls are separated by a sleeve 53 and held in place by the collars 54. Each of the driving rolls is provided with a resilient band or tire 55 of any suitable material.

The shaft 56 extends into a gear box, generally indicated by reference numeral 58 and is provided with a suitable mitre gear 59 which engages with a similar gear 60 on main drive shaft 6I lwhich passes through the various gear boxes and which may be driven at the desired speed by any ordinary motive power.

To accomplish the driving of the initial driving rolls I6 so that they will have a less peripheral speed than any of the succeeding driving rolls I6', this may be done either by making the rolls I 6 slightly smaller than the succeeding rolls I6' or by changing the gear ratio in the gear box. As the simplest means of accomplishing this, the driving rolls I6 are made slightly smaller than the succeeding rolls I6. In the drawings the decreased size of the initial drive rolls has been exaggerated for the purpose of illustration.

In the operation of the device the film is threaded through the various tanks and cabinets, the film passing in loops about the various sections of upper and lower rollers to a take-up reel. At the end of the developing apparatus, where the film emerges completely developed and dried, suflicient tension is placed upon it to draw it away from the last section of upper and lower roller's.

The film enters the developing apparatus by passing around rollers I8 and 22 which serve to put a drag upon the film which the apparatus must overcome. This insures constant feeding of the film into the machine. From these rollers the film passes to roller I3a and then around lower roller Ila and back up to pass around roller I3b and in like manner passes around the remainder of the upper and lower rollers of the first section of rollers, leaving the last upper roller, I3h, to pass to the first upper roller of the next section 28. The film passes around the rollers of this second section and is then conducted about as many succeeding sections of upper and lower rollers as is necessary to carry the required capacity of film through the various tanks and the drying means.

Frictional contact of the film with the rollers I3b, I3c, I3d, I3f, I3g and I3h causes it to be propelled over the first section of upper and lower rollers. It has been found unnecessary to provide driving means for all of the upper rollers I3 and any desirable number of these might be driven. Film passing around the rollers of the second section and each succeeding section of upper and lower rollers is also driven by certain of the upper rollers which are normally peripherally engaged by driving rolls IB'. As the film swells and stretches as it becomes wet by the developing solutions, that is compensated for by the fact that the drive rolls I6 drive the upper rollers I3 which they engage at a peripheral speed slightly greater than the speed of the rollers in the first section 2'I.

The compression springs 45 are set to yieldably hold the upper rollers I3 in engagement with the driving rolls. The springs, with the exception of the first section 2'I, should preferably exert just sufcient force to support the upper rollers and the normal film load. With this construction, whenever any excess or abnormal tension occurs the springs 45 yield and allow the upper rollers I3 to drop out of engagement relation with the drive rolls until such time as the normal tension returns. The springs of the first section preferably exert a greater force than the springs of the succeeding sections so as to insure the iilm being drawn into the developing tank at a constant speed.

With this construction it should be apparent that there can be no danger of mechanically stretching the film. By reason of the fact that the initial driving means operates at a slower speed than lthe succeeding means no slack can develop through elongation of the film during development. Furthermore, the film is fed steadily into the developer solution at a constant controlled speed. We claim as our invention:

l. In film supporting and driving means, the combination of: a frame; a first section of upper and lower film carrying rollers dependently mounted on said frame; a plurality of succeeding sections of upper and lower film carrying rollers dependently mounted on said frame; means for driving certain of the rollers of said first section at a given rate of speed; means for driving certain of the rollers of the succeeding sections at a speed in excess of the speed of the rollers of said first section; and means whereby the rollers of said sections may be disengaged -from their respective driving means when the tension of the film exceeds a given amount.

2. In film supporting a driving means, the combination of a frame; a first section of upper and lower film carrying rollers dependently mounted on said frame; a plurality of succeeding sections of vupper and lower film carrying rollers dependently mounted on said frame; a driving roll rotatably mounted in said frame for engagement with certain of the upper rollers of said first section; succeeding driving rolls rotatably mounted for engagement with certain of the upper rollers of respective succeeding sections, said last men- `tioned driving rolls being of greater diameter than the first mentioned driving roll; and means for rotating said driving rolls.

3. In film supporting and driving means, the combination of: a frame; a first section of upper and lower film carrying rollers dependently mounted on said frame; a plurality o'f succeeding sections of upper and lower film carrying rollers dependently mounted on said frame; a driving roll rotatably mounted in said frame for engagement with certain of the upper rollers of said first section; succeeding driving rolls rotatably mounted for engagement with certain of the upper rollers of respective succeeding sections, said last mentioned driving rolls being oi greater diameter than the first mentioned driving roll; means for rotating said driving rolls; and means whereby the engaged upper rollers may be disengaged from said driving rolls when the tension of said film exceeds a given amount.

4. In flm supporting and driving means, the combination of a frame; a first section of upper and lower film carrying rollers dependently mounted on said frame; a plurality of succeeding sections of upper and lower film carrying rollers dependently mounted on said-frame; a drivingroll rotatably mounted in said frame and adapted to peripherally engage certain of the upper rollers of said first section; succeeding driving rolls rotatably mounted in said frame and adapted to peripherally engage certain of the upper rollers of the succeeding sections; means for driving said driving rolls, said first mentioned driving roll having a peripheral speed less than the speed of the last mentioned driving rolls.

5. In film supporting and driving means for use in a developing tank or the like, the combination of: a frame; a lower shaft dependently mounted on said frame adjacent the bottom of said tank; a plurality of film carrying rollers rotatably mounted on said shaft; an upper shaft dependently mounted on said frame; a plurality of film carrying rollers rotatably mounted on said shaft; a drive shaft rotatably mounted above said upper shaft in said frame; a driving roll rigidly mounted on said drive shaft and adapted to peripheral- 1y engage certain of the film carrying rollers on said upper shaft; means for rotating said drive shaft; and means for permitting said upper shaft to move downwardly to disengage the lm carrying rollers thereon from the driving roll when the tension of the lm exceeds a given amount.

6. In film supporting and driving means for use in a developing tank or the like, the combinatin of: a frame; a plurality of lower nlm carrying rollers rotatably mounted on said frame; a drive shaft rotatably mounted on said frame; a driving roll mounted on said drive shaft; means for rotating said shaft; vertically movable supporting members mounted on said frame; a shaft mounted on said supporting members below said drive shaft; upper film carrying rollers rotatably mounted on said shaft; and means for yieldably holding said supporting members with some of said upper lm carrying rollers in peripheral en.- gagement with said driving roll.

7. In film supporting and driving means for use in a developing tank'or the like, the combination of: a frame; a plurality of lower lm carrying rollers rotatably mounted in said frame adjacent the bottom of the tank; a drive shaft rotatably mounted on said frame; means for rotating said driveshaft; a driving roll mounted on said drive shaft; two pairs of downwardly extending rods vertically slidably mounted on said frame; a cross member connecting each pair of rods at their lower ends; a shaft mounted at each end on the respective cross members; upper film carrying rollers rotatably mounted on said shaft; and spring means associated with said rods whereby some of said upper film carrying rollers are yieldably held in engagement with said driving rollers rotatably mounted on said frame; a

second bank of lower lm carrying rollers rotatably mounted on said frame; a rst drive shaft rotatably mounted in said frame; a second drive shaft rotatably mounted in said frame; means for rotating said shafts; a rst driving roll mounted on said first drive shaft; a second driving roll mounted on said second drive shaft, said second driving roll being larger than said first driving roll; a first set of vertically movable supporting members mounted on said frame; a second set of vertically movable supporting members mounted on said frame; a first shaft mounted on said first set of supporting members; a second shaft mounted on said second set of supporting members, said first and second shafts being below said first and second drive shafts respectively; a rst bank of upper film carrying rollers rotatably mounted on said rst shaft; a second bank of upper film carrying rollers mounted on said second shaft; spring means associated with said rst set of supporting members whereby some of the upper film carrying rollers of said first bank are yieldably held in engagement with said rst driving roll; and spring means associated with said second set of supporting members whereby some of the upper film carrying rollers of said second bank are yieldably held in engagement with said second driving roll.

9. In lm supporting and driving means, the combination of: a frame; a plurality of lower lm carrying rollers rotatably mounted onsaid frame; a plurality of upper lm carrying rollers rotatably mounted on said frame; a drive roll mounted for peripheral engagement with some of the upper rollers; means for rotating said drive roll; and means for permitting said upper rollers to move away from said drive roll to disengage said upper rollers from said drive roll when the tension of the film exceeds a given amount.

10. In lm supporting and driving means, the combination of: a frame; a plurality of lower film carrying rollers rotatably mounted on said frame; a plurality of upper film carrying rollers rotatably mounted on said frame; a drive roll mounted for peripheral engagement with some of said upper rollers; means for rotating said drive roll; and means for yieldably holding said upper rollers in peripheral engagement with said drive roll whereby said upper rollers may be disengaged from said drive roll when the tension of the lm exceeds a given amount.

WILLIAM V. BRENBARGER. JOHN F. VAN LUEVEN. 

